Thymic carcinomas: histopathological varieties and immunohistochemical study.
Thirteen cases of primary thymic carcinomas are described. The patients' ages ranged from 19 to 64 years, with a median of 40 years. Nine of them were male. Chest pain with or without cough was the main presenting symptom. No patient had myasthenia gravis. Five histological types were identified; two were undifferentiated (lymphoepithelioma-like) carcinoma, one was a clear-cell carcinoma, two were mixed squamous and small-cell carcinoma, and six were squamous cell carcinoma. All the tumors were variably positive for anti-keratin antibody AE1 and AE3, but negative for AE2. Anti-neuron specific enolase antibody was useful in identifying and confirming the small-cell carcinoma component of the mixed carcinomas. Anti-epithelial membrane antigen antibody aided in revealing the glandular structures in mixed adenosquamous and small-cell carcinomas. Thymic carcinomas were histopathologically differentiated from thymomas by their malignant cytological appearance, increased mitotic activity, and central tumor necrosis. All six patients with pure squamous-cell carcinoma were still alive, with a median survival time of 27 months. All but one of the other patients of different histological types died, the exception being a recent case of mixed adenosquamous and small-cell carcinoma; their median survival was 19.5 months, or 18 months when the latter surviving case is included. The prognosis of patients with pure squamous-cell carcinoma was better.
Kuo
T T
TT
Department of Pathology, Chang Gung Medical College, Tao Yuan, Taiwan, Republic of China.
Chang
J P
JP
Lin
F J
FJ
Wu
W C
WC
Chang
C H
CH
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D013953:Thymus Neoplasms / Q000378:metabolism / Q000473:pathology*